MAZATLAN BIVALVES 101 



Gasteropod and then deserted, has made a coating over the 

 hole inside. 



146. PLuciNA , sp. ind. 



Tablet 475 contains a fragment of a pinkish shell with very 

 smooth angular ribs. 

 Hah. Mazatlan ; in shell washings ; L'pool Col. 



147. LUCINA PEBURNEA, Reeve. 

 Conch. Icon. Lucina, sp. 49, pi. 8, f. 49. 



Tablet 476 contains a young valve of exquisite beauty which 

 may belong to this species, unless indeed it be a Strigilla lenti- 

 cula. It is of glossy white, and so transparent as to shew the 

 muscular impressions outside, and the external markings within. 

 Suborbicular, with umbo very projecting between two concave 

 margins and nearly central. Surface covered with very crowd- 

 ed concentric striae, which at the margin shew a tendency to 

 commence divarication. It is '06 across. 

 Hob. St.. Elena and Panama, in sandy mud, 11 fm. Cuming. 



? Mazatlan ; one valve in Spondylus washings ; L'pool Col. 



148. LUCINA , sp. ind. 



Tablet 477 contains a fragment of a thin, globose species, 

 with very numerous sharp concentric ridges ; interstices de- 

 cussated by very fine radiating striae. 



Hob. Mazatlan ; fragments of two specimens in shell wash- 

 ings ; L'pool Col. 



GENUS PFIMBEIA, Meg. 



Fimbria, Megerle v. MilMfeld, 1811, Untwurf&c. p. 52. 

 Corbis, Cuv. 1817, Regne An. vol. iii. p. 147. 

 Idothea, Schum. 1817, Essai. 



149. ? FIMBRIA ,jun., sp. ind. 



Tablet 478 contains one of two tiny valves which seem to 

 belong to this genus, having the teeth of Cardium, with con- 



